Sound Waves in Various Media

Acoustic wave motions occur in gas, liquids, organic and inorganic
solids,
in plasmas and superconductors, and in the interplanetary,
interstellar,
and intergalactic media.

Acoustic waves in the surrounding media oscillate at frequencies which
range from billions of cycles per second, to a single cycle within a
period
of several days, months, or years. Acoustic waves propagate at speeds
ranging
from subsonic speeds of several feet per second, to hypersonic speeds
which
approach the speed of light.

The detectable range of sound extends from microacoustic waves produced
by fluctuations of the trapped particles within a sound field, to
macroacoustic
wave disturbances including seismic waves, global waves, solar waves,
and
galactic waves.

Various sound waves are propagated in the Earth's atmosphere,
hydrosphere,
biosphere, and lithosphere, as well as on or near other planetary
bodies
and satellites, in stars and galaxies, in the solar wind, and in
interstellar
dust clouds.